The common rearview mirror of an automotive vehicle is composed of a single piece of silvered glass or plexiglass approximately 5.times.25 centimeters in size. It is mounted near the center of the inner top section of the windshield as illustrated in FIG. 1. The plane of the mirror is oriented in a generally vertical position or is slightly tilted downward by a small pitch angle, and is rotated toward the driver. The angle of rotation or yaw angle, as measured from a vector normal to the mirror surface, is approximately 20 degrees with the vehicle axis of travel. The driver's eyes are approximately 60 centimeters from the mirror which yields a viewing angle of 10 to 20 degrees toward the rear of the vehicle.
To expand this viewing angle, a number of approaches have been tried. The simplest approach is for the driver to move his head from side to side to expand the total viewing angle. This yields only a limited increase in coverage and is a slow an tiring process. Outside rear view mirrors may be used to provide additional lateral coverage. This approach produces a variety of different unrelated views separated by blind spots.
A broader, continuous, viewing angle can only be obtained by increasing the size of the mirror. Wider inside mirrors can be used, but are limited to only a few additional centimeters in width and a correspondingly small increased in viewing angle. The confines of a vehicle limit the length of a planar mirror. A long, linear mirror would have to project forward through the windshield and back into the passenger compartment.
The mirror can be segmented into several independent mirror sections aligned along the top inner edge of the windshield to produce a wide angle view. This approach yields a wide field of vision, but requires a relatively large and bulky assembly, and produces confusing discontinuities as the view shifts from one mirror section to the other.
Convex mirrors expand the viewing angle and avoid the discontinuities, but produce substantial distortion of the reflected objects and misleading perception of their distances to the vehicle.